1. Field of the Invention
The present invention relates to a speaker, a voice coil unit, and a method of manufacturing the voice coil unit, which can be applied to a slim-type speaker for liquid crystal televisions, PDP televisions, home audio devices, desktop and notebook personal computers, and the like. More specifically, the present invention relates to a speaker, a voice coil unit, and a method of manufacturing the voice coil unit, in which a voice coil section is provided, the voice coil section having a coil member wound in a planar track shape so as to extend through a planar-type coil bobbin section from one side to the other side and from the other side to the one side, and which makes it possible to reduce thermal deformation due to a bimetal phenomenon resulting from a difference between the thermal expansion coefficient of the coil member and the thermal expansion coefficient of the coil bobbin member, and maintain the planarity of the coil bobbin member.
2. Description of the Related Art
In recent years, with the proliferation of slim-type televisions using a liquid crystal display device or plasma display device (PDP), there is a demand for thin-type and slim-type speakers and the like. Examples of the shape of the voice coil for realizing thin-type and slim-type speakers range from a common cylindrical shape to a planar shape.
In connection with a planar-type speaker of this kind, Japanese Unexamined Patent Application Publication No. 2002-223495 discloses a slim-type speaker that can be used in various audio devices and video devices. This speaker includes a magnetic circuit, a frame, a diaphragm, a damper, and a voice coil, and a slit-like magnetic gap is provided in the magnetic circuit. The frame is coupled to this magnetic circuit. The outer peripheral edges of the diaphragm are coupled to the frame. The planar voice coil is coupled to the diaphragm and passed through the magnetic gap of the magnetic circuit, and is supported by the damper coupled to the magnetic circuit. In this speaker, the damper is provided with a through-hole, and a part or the whole of the lower portion of the voice coil is inserted into this through-hole, thereby coupling the damper and the voice coil together. When the speaker is configured in this way, a highly reliable speaker that delivers deep bass and high input tolerance can be provided.